Can I correct my last name if my taxes have been filed already and pending

[ineed1160]

I work overnight and added a extra letter

[CatinaT1]

It depends on if it gets accepted or rejected. The IRS checks the first four letters of your last name with the last four digits of your ssn. If those are correct, it will go through and you will not be able to change it. Just make sure next year you have it correct.

[VolvoGirl]

Wait and see if your returns gets Accepted or Rejected.  If it rejects you can change it.  If the IRS accepts it then see what the IRS does about it.